Light guide for low profile luminaire

ABSTRACT

A luminaire comprising a heat sink, a light source and a light guide. The light source is carried by the heat sink and configured to emit a source light. The light source includes a heat spreader having an inner surface and an outer surface, and a plurality of light-emitting diodes (LEDs) carried by a circuit board and disposed generally along an outer peripheral perimeter portion of the inner surface of the heat spreader, and positioned in thermal communication with the heat spreader. The light guide includes a lens with a plurality of optical elements disposed within the lens.

RELATED APPLICATIONS

This application is a continuation and claims the benefit under 35U.S.C. §120 of U.S. patent application Ser. No. 15/248,769 titled LightGuide for Low Profile Luminaire, and filed on Aug. 26, 2016, which is,in turn, a continuation-in-part and claims the benefit of U.S. patentapplication Ser. No. 14/863,150, now U.S. Pat. No. 9,435,930 titled LowProfile Luminaire And Associated Systems And Methods filed Sep. 23,2015, which is, in turn, a continuation of U.S. patent application Ser.No. 14/014,512, now U.S. Pat. No. 9,157,581 titled Low Profile LuminaireWith Light Guide And Associated Methods filed Aug. 30, 2013, which is,in turn, a continuation-in-part of U.S. patent application Ser. No.13/476,388, now U.S. Pat. No. 8,672,518 titled Low Profile Light andAccessory Kit For The Same filed May 21, 2012, which is, in turn, acontinuation-in-part of U.S. patent application Ser. No. 12/775,310, nowU.S. Pat. No. 8,201,968 titled Low Profile Light filed May 6, 2010,which claims the benefit of U.S. Provisional Patent Application Ser. No.61/248,665 filed Oct. 5, 2009, the entire contents of each of which areincorporated herein by reference, except to the extent that anydisclosure herein conflicts with the disclosure therein.

FIELD OF THE INVENTION

The present invention relates to low profile luminaires and, morespecifically, to luminaires that employ light guides, and associatedsystems and methods.

BACKGROUND

Recessed light fixtures (also known as “canister” fixtures) andflush-mount electrical boxes (also known as “junction” boxes) arecommonly used in indoor and outdoor downlight applications. Examples ofindustry standard can-canister fixtures are illustrated as fixture 800at FIG. 8 and fixture 900 at FIG. 9. Examples of industry standardjunction boxes are illustrated as boxes 1000, 1100, and 1200 at FIGS.10, 11, and 12, respectively. Both canister fixtures and junction boxesmay be installed in a hollow opening in a ceiling or other surface.Canister fixtures commonly feature a lamp socket configured to receivean incandescent lamp or compact fluorescent lamp (“CFL”).

Both incandescent and fluorescent lamp types suffer from certaindisadvantages. For example, incandescent lamps convert approximately 3%of electrical power consumed into usable light, while the remaining 97%of power may be wasted as heat. Compared to an incandescent lamp, afluorescent lamp converts electrical power into useful light moreefficiently, delivers a significantly longer useful life, and presents amore diffuse and physically larger light source. However, fluorescentlamps are typically more expensive to install and operate than anincandescent lamp because of the requirement for a ballast to regulatethe electrical current. Many fluorescent lamps have poor colortemperature, resulting in a less aesthetically pleasing light. Also, ifa fluorescent lamp that uses mercury vapor is broken, a small amount ofmercury (classified as hazardous waste) can contaminate the surroundingenvironment.

Digital lighting technologies such as light-emitting diodes (LEDs) offersignificant advantages over legacy lamps. These advantages include, butare not limited to, better lighting quality, longer operating life, andlower energy consumption. Consequently, LED-based lamps increasingly arebeing used not only in original product designs, but also in productsdesigned to replace legacy lamps in conventional lighting applicationssuch as canister-based downlights. However, a number of installationchallenges and costs are associated with replacing traditional lampswith LED illumination devices. The challenges, which are understood bythose skilled in the art, include light output, thermal management, andease of installation. The costs, which are similarly understood by thoseskilled in the art, typically stem from a need to replace or reconfigurea canister fixture configured to support traditional lamps to supportLEDs instead.

By the very nature of their design and operation, LEDs have adirectional light output. Consequently, employing LEDs to produce lightdistribution properties approximating or equaling the light dispersionproperties of traditional lamps may require the costly andlabor-intensive replacement or reconfiguration of the host lightfixture, and/or the expensive and complexity-introducing design ofLED-based solutions that minimize the installation impact to the hostlight fixture. Often material and manufacturing costs are lost in thistrade off. Also, light distribution design choices such as largeparabolic reflectors and multiple optics operate contrary to theobjective of presenting a low profile lighting device as fullyassembled.

Another challenge inherent to operating LEDs is heat. Thermal managementdescribes a system's ability to draw heat away from an LED. Passivecooling technology, such as a heat sink thermally coupled to a digitaldevice, may be used to transfer heat from a solid material to a fluidmedium such as, for example, air. LEDs suffer damage and decreasedperformance when operating in high-heat environments. Moreover, whenoperating in a high-temperature ambient environment and/or aspace-limited enclosure, the heat generated by an LED and its attendingcircuitry can cause damage to the LED. Heat sinks are well known in theart and have been effectively used to provide cooling capacity, thusmaintaining an LED-based lamp within a desirable operating temperature.However, heat sinks can sometimes negatively impact the lightdistribution properties of lighting solution, resulting in non-uniformdistribution of light about the fixture. Heat sink designs also may addto the weight and/or profile of an illumination device, therebycomplicating installation, and also may limit available space for othercomponents needed for delivering light.

Replacement of legacy lighting solutions may be complicated by the needto adapt LED-based devices to meet legacy form standards. For example,in a commercial lighting system retrofit, disposal of a replaced lamp'sfixture housing often is impractical. Consequently, retrofit canisterdownlights often are designed to adapt to a legacy housing, bothfunctionally and aesthetically. Also, power supply requirements ofLED-based lighting systems can complicate installation of LEDs as aretrofit to existing light fixtures. LEDs are low-voltage light sourcesthat require constant DC voltage or current to operate optimally, andtherefore must be carefully regulated. Too little current and voltagemay result in little or no light. Too much current and voltage candamage the light-emitting junction of the LED. LEDs are commonlysupplemented with individual power adapters to convert AC power to theproper DC voltage, and to regulate the current flowing through duringoperation to protect the LEDs from line-voltage fluctuations. Thelighting industry is experiencing advancements in LED applications, someof which may be pertinent to improving the design of low profilecanister downlighting solutions.

U.S. Pat. No. 7,178,946 to Saccomanno et al. discloses a luminairedevice that includes a tubular fluorescent bulb that is partiallysurrounded on an underside by a curved reflector. Light rays from thebulb are directed towards the curved reflector and reflected towards acollimator. A light guide featuring a refractive slab captures the lightoutput from the collimator and redirects the light away from the devicein a uniform luminance. However, employing legacy lamp technology mayresult in a design that suffers light losses (both to reflection and toabsorption).

U.S. Pat. No. 8,328,406 to Zimmerman is directed to an illuminationsystem that employs a discrete light source, a reflector, and first andsecond substantially flat light guides. This lighting solution requiresembedding the discrete light source, such as an LED, into acentrally-located region in the second light guide. Light emitted fromthe light source enters and propagates to the edge of the second lightguide, where the reflector reflects light emerging from the edge of thesecond light guide back into the edge of the first light guide. Opticalelements that increase in density from the edge to the center of thefirst light guide redirect the light to emit at a substantially uniformintensity from the surface of the first light guide. However,sandwiching a light-confining interface layer between multiple lightguides operates contrary to the objectives of constructing a low profileluminaire and minimizing design and manufacturing complexity.

U.S. Pat. No. 6,647,199 to Pelka at al. discloses a low profile lightingapparatus that includes a light guide coupled to a light source forinjecting light into the light guide. In one embodiment, multiple lightsources surrounded by diffusive reflective material may introduce lightat spaced peripheral locations along the edge of a rectangularly-shapedlight guide. However, because the majority of light injected into theedge of the light guide originates from directional-light generatingLEDs, a complex plurality of display elements must be designed into thelight guide to shape light propagating through the light guide into asubstantially uniform illumination profile.

Accordingly, and with the above in mind, a need exists for a low profileluminaire that may be employed within the volume of space available inan existing canister light fixture, and that efficiently deliversimproved lighting quality compared to traditional lamps. Morespecifically, a need exists for a canister-based lighting solution thatmay benefit from the advantages of digital lighting technology, whileexhibiting a more uniform illumination profile than legacy downlightsolutions. Additionally, a need exists for a luminaire designed for easeof installation as well as for manufacturing cost reduction.

This background information is provided to reveal information believedby the applicant to be of possible relevance to the present invention.No admission is necessarily intended, nor should be construed, that anyof the preceding information constitutes prior art against the presentinvention.

SUMMARY OF THE INVENTION

A luminaire comprising a heat sink, a light source and a light guide.The light source may be carried by the heat sink and configured to emita source light. The light source may include a heat spreader having aninner surface and an outer surface, and a plurality of light-emittingdiodes (LEDs) carried by a circuit board and disposed generally along anouter peripheral perimeter portion of the inner surface of the heatspreader, and positioned in thermal communication with the heatspreader. The light guide may include a lens with a plurality of opticalelements disposed within the lens.

In some embodiments, the plurality of optical elements may bemicro-lenses and the micro lenses may be configured to scatter light inmore than one direction. The micro-lenses may also be configured toconcentrate light in more than one direction.

In other embodiments, the plurality of optical elements may be liquidfilled or gas filled and still in other embodiments the plurality ofoptical elements may be one of plastic and glass. Furthermore, theluminaire may include a combination of the light source and the heatsink dimensioned so as to cover an opening defined by a nominally sizedfour-inch can light fixture, and to cover an opening defined by anominally sized four-inch electrical junction box.

In another embodiment, the luminaire may include a heat sink, a lightsource and a light guide. The light source may be carried by the heatsink and configured to emit a source light. The light source includes aheat spreader having an inner surface and an outer surface, and aplurality of light-emitting diodes (LEDs) carried by a circuit board anddisposed generally along an outer peripheral perimeter portion of theinner surface of the heat spreader, and positioned in thermalcommunication with the heat spreader. The light guide may include a lenswith a plurality of optical elements including light scatteringparticles disposed within the lens. The light scattering particles maybe one of glass, ceramic, rubber, silica, inorganic material, andphosphor. Furthermore, the plurality of optical elements may be one ofcircular, oval, rectangular, square, and polygonal in shape.

In other embodiments, the plurality of optical elements may bemicro-lenses and the micro-lenses may be configured to scatter light inmore than one direction or may be configured to concentrate light inmore than one direction. This embodiment may also include a combinationof the light source and the heat sink dimensioned so as to cover anopening defined by a nominally sized four-inch can light fixture, and tocover an opening defined by a nominally sized four-inch electricaljunction box.

In yet another embodiment, the luminaire may include a heat sink, alight source and a light guide. The light source may be carried by theheat sink and configured to emit a source light. The light source mayinclude a heat spreader having an inner surface and an outer surface,and a plurality of light-emitting diodes (LEDs) carried by a circuitboard and disposed generally along an outer peripheral perimeter portionof the inner surface of the heat spreader, and positioned in thermalcommunication with the heat spreader. The light guide may include apropagation region including a lens with solid optical elementsincluding light scattering particles made from at least one of glass,ceramic, rubber, silica, inorganic material, and phosphor material, andnon-solid optical elements comprising liquid and gas. In thisembodiment, the lens may include a plurality of micro-lenses and thelight guide may be configured to scatter and concentrate light inmultiple directions. The micro-lenses may be one of circular, oval,rectangular, square, and polygonal in shape.

In this embodiment, a combination of the light source and the heat sinkmay be so dimensioned as to cover an opening defined by a nominallysized four-inch can light fixture, and sized to cover an opening definedby a nominally sized four-inch electrical junction box. Furthermore, acombination of the light source and the heat sink may also be sodimensioned as to cover an opening defined by a nominally sizedfour-inch can light fixture, and sized to cover an opening defined by anominally sized four-inch electrical junction box.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an assembled, perspective bottom view of a low profileluminaire according to an embodiment of the present invention.

FIG. 1B is an exploded perspective view of the low profile luminaireillustrated in FIG. 1A.

FIG. 1C is an assembled, front elevation view of the low profileluminaire illustrated in FIG. 1A.

FIG. 1D is an assembled, cross-sectional view of the low profileluminaire illustrated in FIG. 1A and taken through line 1D-1D of FIG.1C.

FIG. 2 is a schematic cross-sectional view of an exemplary illuminationassembly of a low profile luminaire according to an embodiment of thepresent invention.

FIG. 3A is a perspective bottom view of a heat sink of the low profileluminaire depicted in FIG. 1B.

FIG. 3B is a perspective top view of the heat sink depicted in FIG. 3A.

FIG. 4A is a perspective inner view of a light source of the low profileluminaire depicted in FIG. B.

FIG. 4B is a perspective outer view of the light source depicted in FIG.4A.

FIG. 5 is an assembled, perspective top view of the low profileluminaire depicted in FIG. 1A.

FIG. 6 is a schematic block diagram of a low profile luminaire accordingto an embodiment of the present invention.

FIG. 7 is a flow chart detailing methods of assembling a low profileluminaire according to an embodiment of the present invention.

FIGS. 8-12 depict isometric views of canister-type light fixtures andelectrical junction boxes according to the prior art for use inaccordance with an embodiment of the present invention.

FIG. 13 is a top view of a light guide a low profile luminaire accordingto an embodiment of the present invention.

FIG. 14 a side view of the light guide depicted in FIG. 13.

FIG. 15 is a cross-section view of the light guide of FIG. 14 along thesection A-A in FIG. 14.

FIG. 16 is a magnified portion of the cross-section view of the lightguide of FIG. 15.

FIG. 17 is a block diagram representation of a machine in the exampleform of a computer system according to an embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Those ofordinary skill in the art realize that the following descriptions of theembodiments of the present invention are illustrative and are notintended to be limiting in any way. Other embodiments of the presentinvention will readily suggest themselves to such skilled persons havingthe benefit of this disclosure. Like numbers refer to like elementsthroughout.

Although the following detailed description contains many specifics forthe purposes of illustration, anyone of ordinary skill in the art willappreciate that many variations and alterations to the following detailsare within the scope of the invention. Accordingly, the followingembodiments of the invention are set forth without any loss ofgenerality to, and without imposing limitations upon, the claimedinvention.

In this detailed description of the present invention, a person skilledin the art should note that directional terms, such as “above,” “below,”“upper,” “lower,” and other like terms are used for the convenience ofthe reader in reference to the drawings. Also, a person skilled in theart should notice this description may contain other terminology toconvey position, orientation, and direction without departing from theprinciples of the present invention.

Furthermore, in this detailed description, a person skilled in the artshould note that quantitative qualifying terms such as “generally,”“substantially,” “mostly,” and other terms are used, in general, to meanthat the referred to object, characteristic, or quality constitutes amajority of the subject of the reference. The meaning of any of theseterms is dependent upon the context within which it is used, and themeaning may be expressly modified.

Referring now to FIGS. 1A-13, a low profile luminaire 100 according toan embodiment of the present invention is now described in detail.Throughout this disclosure, the present invention may be referred to asa luminaire 100, a lighting system, an LED lighting system, a lampsystem, a lamp, a device, a system, a product, and a method. Thoseskilled in the art will appreciate that this terminology is onlyillustrative and does not affect the scope of the invention. Forinstance, the present invention may just as easily relate to lasers orother digital lighting technologies.

Example systems and methods for a low profile luminaire are describedherein below. In the following description, for purposes of explanation,numerous specific details are set forth to provide a thoroughunderstanding of example embodiments. It will be evident, however, toone of ordinary skill in the art that the present invention may bepracticed without these specific details and/or with differentcombinations of the details than are given here. Thus, specificembodiments are given for the purpose of simplified explanation and notlimitation.

Referring now to FIGS. 1A, 1B, 1C, and 1D, a low profile luminaire 100configured to be carried by a light fixture (such as the fixture typesillustrated, for example, in FIGS. 8-12) will now be discussed.Referring more specifically to FIGS. 1A and 1B, the luminaire 100,according to an embodiment of the present invention, may include a heatgenerating element 110 in the form of a light source, a heat sink 120thermally coupled to and disposed diametrically outboard of the lightsource 110, a reflector 130 in optical communication with and disposeddiametrically inboard of the light source 110, and a light guide 140positioned in optical communication with at least one of the lightsource 110 and the reflector 130 and disposed therebetween.Additionally, the luminaire 100 may further include a mounting bracket122, a gap pad 112, a mounting ring 150, and a trim cover 152.

Although luminaire 100 is depicted as circular in shape in FIGS. 1A-1D,luminaire 100 and its constituent components may have any of a varietyof other shapes, including quadrilateral or polygonal. Regardless of theshape of the luminaire 100, light may be emitted from the light source110 and reflected by reflector 130 into the light guide 140 aboutsubstantially the entire perimeter of the light guide 140. The lightguide 140 may after the light to project a uniform illuminance into theenvironment exterior to the luminaire 100. One or more of the componentscomprising the luminaire 100 may be connected by any means or methodknown in the art, including, not by limitation, use of adhesives orglues, welding, interference fit, and fasteners 158. Alternatively, oneor more components of the luminaire 100 may be molded duringmanufacturing as an integral part of the luminaire 100.

Referring now to FIGS. 3A and 3B, and continuing to refer to FIGS. 1Aand 1B, the heat sink 120 of the luminaire 100, according to anembodiment of the present invention, is discussed in greater detail.Thermal management capability of the luminaire 100 according to anembodiment of the present invention may be provided by a heat sink 120.Although a single heat sink 120 is depicted in the appended figures,those skilled in the art will appreciate that more than one heat sinkmay be provided while still accomplishing the goals, features andobjectives of the present invention.

The heat sink 120 may be configured to be thermally coupled to one ormore components of the luminaire 100 so as to increase the thermaldissipation capacity of the luminaire 100. The heat sink 120 may have abottom surface (illustrated, for example, in FIG. 3A) and a top surface(illustrated, for example, in FIG. 3B). The heat sink 120 may include abase 312 configured to communicate thermally with the heat generatingelement 110, and a sidewall 314 configured to provide a larger surfacearea than otherwise may be provided by surfaces of the heat generatingelement 110 and the base 312.

Referring again to FIG. 1C, the heat sink 120 may be characterized bythe sidewall 314 having an overall outside height H and the base 312having an overall outside dimension D such that the ratio of H/D isequal to or less than 0.25. Although a ratio of 0.25 or less of H/D ispreferred, those skilled in the art will appreciate that the presentinvention contemplates a ratio of greater than 25 of H/D as well.Dimensions for H and D are contemplated such that the heat sink 120 maybe configured and sized so as to (i) cover an opening defined by anindustry standard can-type light fixture having nominal sizes from threeto six inches (see fixture 800 at FIG. 8 and fixture 900 at FIG. 9, forexample), and (ii) cover an opening defined by an industry standardelectrical junction box having nominal sizes from three to six inches(for example, see boxes 1000, 1100, and 1200 at FIGS. 10, 11, and 12,respectively). The base 312 of the heat sink 120 may be configured intoany shape, including a circle, ovoid, square, rectangle, triangle, orany other polygon. For example, and without limitation, the heat sink120 illustrated in FIGS. 3A and 3B demonstrates a circularconfiguration. Also for example, and without limitation, the base 312and the sidewall 314 may be integrally molded to form the heat sink 120as a monolithic unit.

The sidewall 314 of the heat sink 120 may be in the form of one or morerims. For example, and without limitation, portions of a heat sink 120may include one or more rims 314 that may be coupled with and positionedsubstantially perpendicular to the base 312, the combination of whichmay form a recess 316. In the embodiment of the invention illustrated inFIGS. 3A and 3B, the rim 314 may be configured to define an outerperimeter of the heat sink 120 and to project radially outward from thebottom surface of the generally annular base 312. For example, andwithout limitation, the single rim 314 may define a curved frame thatmay advantageously provide additional surface area to supportdissipation of heat. Those skilled in the art will appreciate, however,that the present invention contemplates the use of rims 314 of anyshape, and that the disclosed heat sink 120 that includes rims 314 thatform a curved frame is not meant to be limiting in any way.

Continuing to refer to FIG. 3B, a top surface 320 of the heat sink 120may include one or more channels 326. For example, and withoutlimitation, the rim 314 may comprise an inner wall 322 and an outer wall324 that, in combination, may form the hollow channel 326. Employment ofthe channel 326 may increase the surface area of the heat sink 120 andmay permit thermal fluid flow between adjacent inner and outer walls322, 324, thereby enhancing the heat transfer capability of the heatsink 120. For example, and without limitation, the rim 314 may have ashape that may promote localized air movement within the one or morechannels 326 due at least in part to localized air temperature gradientsand resulting localized air pressure gradients.

Without being held to any particular theory, it is contemplated that thechannel 326 having a narrow end and an opposing broad end may generatelocalized air temperatures in the narrow end that are higher thanlocalized air temperatures in the associated broad end, due to thedifference of proximity of the inner and outer walls 322, 324 of theassociated channel. More specifically, the width of the channel 326(measured from the inner wall 322 to the outer wall 324 of rim 314, andalong a plane parallel with the plane defined by the base 312) maydecrease in a radial direction from the plane of the base 312 to theintersection of the inner and outer walls 322, 324. The presence of suchair temperature gradients, with resulting air pressure gradients, withina given channel 326 may cause localized air movement within theassociated void, which in turn may enhance the overall heat transfer ofthe thermal system (the thermal system being the luminaire 100 as awhole). Those skilled in the art will readily appreciate, however, thatthe rims 314 of the heat sink 120 may be configured in any way whilestill accomplishing the many goals, features and advantages according tothe present invention.

Still referring to FIG. 3B, the channel 326 may be configured to havespatial characteristics permitting fluid flow within the channel 326.For example, and without limitation, the fluid flow within the channel326 may cause the transfer of heat from the light source 110 through thebase 312 of the heat sink 120, which may then transfer the heat to therims 314 and subsequently to the environment either internal or externalto the luminaire 100 where the heat may dissipate. Accordingly, thespatial characteristics of the channel 326 may directly correspond tothe amount of heat that can be transported from the luminaire 100 to thedissipating environment. Spatial characteristics that can be modifiedmay include total volume, fluid flow characteristics, interior surfacearea, and exterior surface area. For example, and without limitation,one or more surfaces of the heat sink 120 may be textured or includegrooves to increase the surface area of the heat sink 120, therebyfacilitating thermal transfer thereto. Moreover, thermal properties ofthe materials used to form the heat sink 120 may be considered informing the thermal management system for the luminaire 100.

The aforementioned spatial characteristics may be modified toaccommodate the heat generated by the light source 110 of the luminaire100. For instance, the volume of the channel 326 may be directlyproportional to the thermal output of the luminaire 100. Similarly, asurface area of some part of the heat sink 120 may be proportional tothe thermal output of the luminaire 100. In any case, the channel 326may be configured to maintain the temperature of the luminaire 100 atthermal equilibrium or within a target temperature range.

Continuing to refer to FIG. 3B, the heat sink 120 also may serve as atrim plate for the luminaire 100. Because canister-type light fixturesand ceiling/wall mount junction boxes are designed for placement behinda ceiling or wall material, the heat sink 120 may be characterized by asubstantially flat top surface 320, thereby permitting the luminaire 100to sit substantially flush on the surface of the ceiling/wall material.For example, and without limitation, the heat sink 120 may include thechannel 326 as described above being V-shaped, thereby causing the heatsink 120 to present a frustoconical shape as illustrated in FIGS. 1A and3A. Additionally, in some embodiments, the rim 314 may be configured soas to interface with and/or sit flush on the surface of the ceiling/wallmaterial.

The heat sink 120 may be made by molding, casting, or stamping of athermally conductive material. Materials may include, withoutlimitation, thermoplastic, ceramics, porcelain, aluminum, aluminumalloys, metals, metal alloys, carbon allotropes, and compositematerials. Additional information directed to the use of heat sinks fordissipating heat in an illumination apparatus is found in U.S. Pat. No.7,922,356 titled Illumination Apparatus for Conducting and DissipatingHeat from a Light Source, and U.S. Pat. No. 7,824,075 titled Method andApparatus for Cooling a Light Bulb, the entire contents of each of whichare incorporated herein by reference.

Referring now to FIGS. 2, 4A and 4B, and referring again to FIG. 1B, thelight source 110 of the luminaire 100 according to an embodiment of thepresent invention is now discussed in greater detail. The light source110 may comprise one or more light-emitting elements 216. Each of thelight-emitting elements 216 may be any device capable of or method ofemitting light. Such devices and methods may include, withoutlimitation, light-emitting semiconductors, lasers, incandescent,halogens, arc-lighting devices, fluorescents, and any other digitallight-emitting devices or methods known in the art. In the presentembodiment, the light-emitting elements 216 may be light-emittingsemiconductors such as, for example, light-emitting diodes (LEDs).

In some embodiments of the present invention, the light source 110 maybe an LED package. As illustrated in FIG. 4A, for example, and withoutlimitation, the light source 110 may be an LED package that may includeone or more LEDs 216 and a heat spreader 214. The heat spreader 214 maybe a component that completes a heat transfer path from the LEDs 216 tothe heat sink 120, but that does not itself dissipate enough heat fromthe LEDs 216 to be considered a heat sink. For example, and withoutlimitation, the heat spreader 214 may comprise a printed circuit board.The LEDs 216 may be disposed on and operably coupled to the printedcircuit board 214. The LEDs 216 may be distributed about the innersurface 406 of the printed circuit board 214 in any desirable pattern,configuration, or arrangement. For example, and without limitation, theLEDs 216 may be disposed generally along the periphery of the printedcircuit board 214. Also for example, where the printed circuit board 214may be divided into two coplanar sections, one section of the printedcircuit board 214 may have disposed thereon more LEDs 216 than on theother section. As another example, the LEDs 216 may be distributed aboutthe printed circuit board 214 substantially evenly. The distribution ofLEDs 216 on the printed circuit board 214, and the distribution oflight-emitting elements generally, may affect the propagation of lightinto the recess 316 of the heat sink 120, the intensity of lightincident upon the light guide 140 and, ultimately, the light emissioncharacteristics of the luminaire 100. Additionally, the LEDs 216 mountedto the printed circuit board 214 may emit light within differentwavelength ranges, and the distribution of the LEDs 216 having differingwavelength ranges may similarly affect the light emissioncharacteristics of the luminaire 100.

The printed circuit board 214 of the light source 110 may be sized tocouple to the base 312 of the heat sink 120. In the luminaire 100presented in an assembled position as illustrated, for example, in FIG.1D, the perimeter of the base 312 of the heat sink 120 may be alignedwith a respective perimeter of the light source 110. Therefore, theprinted circuit board 214 may generally define the shape of the lightsource 110 such that the light source 110 may be disposed fittedly inthe recess 316 of the heat sink 120. The printed circuit board 214 maybe configured to have a geometric frame configuration substantially asdescribed for the light source 110 described hereinafter.

The printed circuit board 214 may be configured to be functionally,electrically, and/or mechanically coupled to the LEDs 216. The printedcircuit board 214 may include necessary circuitry so as to enable theoperation of the LEDs 216. For example, and without limitation, one ormore electrical supply lines (not shown) may be disposed in electricalcommunication with the light source 110. The printed circuit board 214may further include electrical contacts 426. Each of the electricalcontacts 426 may be electrically connected to a respective one of theLEDs 216, thereby enabling the operation of the LEDs 216. Additionally,the electrical contacts 426 may be configured to interface with andelectrically couple to one or more electrical connectors 428 that cansupply electrical power from the electrical supply lines to theelectrical contacts 426, thereby enabling the operation of the LEDs 216.

Additionally, the electrical contacts 426 may be configured to enablethe selective operation of each of the LEDs 216 by permitting operatingsignals to be transmitted therethrough. For example, and withoutlimitation, the printed circuit board 214 may include the necessarycircuitry so as to enable individual operation of each of the LEDs 216.Other embodiments of the light source 110 may include light-emittingelements 216 other than LEDs, but may include a structure similar to theprinted circuit board 214 that enables the operation of thelight-emitting elements 216.

Each of the light-emitting elements 216 may emit light within awavelength range. More specifically, each of the light-emitting elements216 may emit light having a wavelength range within the range from about390 nanometers to about 750 nanometers, commonly referred to as thevisible spectrum. Additionally, in some embodiments, the light-emittingelements may emit light having a wavelength within the range from about200 nanometers to about 390 nanometers, commonly referred to asultraviolet light. Each of the light-emitting elements 216 may emitlight having a wavelength range identical or similar to the wavelengthrange to another of the light-emitting elements 216, or it may emitlight having a wavelength range different from another of thelight-emitting elements 216. The selection of light-emitting elements216 included in the light source 110 may be made so as to produce adesirous combined light, as described hereinabove. Accordingly, thelight source 110 may include light-emitting elements 216 that producelight having a variety of wavelengths such that the emitted lightcombines to form a combined polychromatic light. In some embodiments,the combined light may be observed by an observer in the environmentexternal the luminaire 100 as a generally white light.

Moreover, the combined light may have desirous characteristics, such ascertain color temperatures and color rendering indices. The methods offorming such a combined light are discussed in the referencesincorporated by reference hereinabove. For example, the light source 110may include light-emitting elements 216 that emit light that combines toproduce a combined light that is generally white in color or any othercolor such as those represented on the 1931 CIE color space, having acolor temperature within the range from about 2,000 Kelvin to about25,000 Kelvin, and/or having a coloring rendering index within the rangefrom about 15 to about 100. Moreover, in addition to includinglight-emitting elements 216 to produce a combined light having desirouscharacteristics, the luminaire 100 may include one or more colorconversion layers configured to convert light from a first sourcewavelength to a second converted wavelength as described in greaterdetail hereinabove and hereinbelow.

Continuing to refer to FIGS. 1B and 4B, the heat sink 120 may bepositioned adjacent an outer surface 424 of the heat spreader 214 of thelight source 110, and may be thermally coupled to the light source 110.Optionally, a gap pad 112 may be positioned between the heat sink 120and the outer surface 424 of the light source 110. Thermal coupling maybe accomplished by any method, including thermal adhesives, thermalpastes, thermal greases, thermal pads, and all other methods known inthe art. Where a thermal adhesive, paste, or grease is used, the heatsink 120 may be connected to any part of the light source 110 as mayeffectively cause thermal transfer between the light source 110 and theheat sink 120. The method of thermal coupling may be selected based oncriteria including ease of application/installation, thermalconductivity, chemical stability, structural stability, and constraintsplaced by the luminaire 100.

Connection point locations for one or more LEDs 216 may depend at leastpartially on the heat distribution within the light source 110. Forexample, the heat sink 120 may be thermally coupled directly to one ormore LEDs 216, indirectly to the LEDs 216 which may be thermally coupledto the heat spreader 214, or both. As described above, the heat spreader214 may be in the form of a printed circuit board. In application, theLED package may generate heat at the junction of each LED die 216. Toprovide for suitable heat transfer from the LEDs 216 to the heat sink110, an embodiment may employ a plurality of interconnecting threads 426which provide suitable surface area for heat transfer thereacross.

For example, and without limitation, the substantially flat base 312 ofthe heat sink 120 (as illustrated in FIG. 3A) may come into thermalcontact with the outer surface 424 of the printed circuit board 214 ofthe light source 110. The one or more rims 314 of a heat sink 120 may bepositioned peripheral to the surface of the base 312 with which thelight source 110 makes contact. Accordingly, and as may be understood bythose skilled in the art, the heat sink 120 advantageously may provideadditional surface area for heat that may be produced by the lightsource 110 to be dissipated. Additionally, the base 312 of the heat sink120 also may be configured to make mechanical contact with the outersurface 424 of the light source 110, thereby providing for the heat sink120 to carry the light source 110 and/or fixing the orientation of thelight source 110 within the luminaire 100 during normal operation. Forexample, and without limitation, the light source 110 and the base 312of the heat sink 120 may be configured to have substantially matchingshapes, such as a circle (otherwise known as a disk), an oval, a square,a rectangle, a triangle, a regular polygon, and an irregular polygon.

Referring again to FIGS. 1B and 2, an illumination assembly, which maycomprise the light source 110, the reflector 130, and the light guide140, will now be discussed in more detail. In the present embodiment,the light source 110 may include a reflective layer 218 disposed on theprinted circuit board 214 on a surface to which the LEDs 216 may beattached or adjacent to, and in any case the surface of the printedcircuit board 214 upon which light emitted by the LEDs 216 may beincident upon. The reflective layer 218 may be positioned so as to coverthe inner surface 406 of the printed circuit board 214, while permittingthe one or more LEDs 216 to be uncovered. The reflective layer 218 mayefficiently reflect light from the LEDs 120 away from the printedcircuit board 214 and toward other luminaire components present in therecess 316. More specifically, the reflective inner surface 406 of theprinted circuit board 214 may reflect light incident thereupon back intothe recess 316, thereby reducing the loss of light that otherwise wouldnot be reflected by the printed circuit board 214.

While FIG. 2 includes the reflective layer 218, it will be appreciatedthat not all embodiments of the invention disclosed herein may employ areflective layer 218, and that when a reflective layer 218 is employedit may be used for certain optical preferences and/or to mask othercomponents, such as electronics, that may be positioned opposite theinner surface 406 of the printed circuit board 214 of the luminaire 100.For example, and without limitation, the surface of the reflective layer218 may be white, reflective polished metal, or metal film over plastic,and may have surface detail for certain optical effects, such as colormixing or controlling light distribution and/or focusing.

The light source 110 may be desirously positioned within the luminaire100. For example, and without limitation, the light source 110 may bepositioned within the luminaire 100 such that light that propagatesthrough complementary components of the luminaire 100 and into theenvironment surrounding the luminaire 100 is generally controlled. As afurther example, the light source 110 may be positioned such that thelight source 110 is not visible from any point in the environmentexternal the luminaire 100, the environment generally defined as ahemisphere beneath the heat sink 120. Similarly, the light source 110may be positioned such that light emitted from the light source 110 isnot directly observable from any point in the environment external theluminaire 100. For example, any light that is visible from a point inthe environment external the luminaire 100 may be reflected at leastonce, such as light that is reflected from the reflective layer 218.

Referring again to FIGS. 1B and 2, the reflector 130 of the luminaire100 according to an embodiment of the present invention is now discussedin greater detail. The reflector 130 may have an interior regionconfigured for receiving light from the light source 110. For example,and without limitation, light emitted by one or more LEDs 216 may beincident upon the interior region of the reflector 120. In a preferredembodiment, one or more LEDs 216 present in the light source 110 may bepositioned to emit light in a direction that may be at an angle notperpendicular to the orientation of the interior region of the reflector130.

The reflector 130 may be formed into any geometric configuration so asto position the interior region generally coextensive with thepositioning of the one or more LEDs 216. In the present embodiment, thereflector 130 is formed into a generally annular configuration (alsoknown as ring-shaped). More specifically, the reflector 130 may beformed into an annular configuration to define an aperture 132. Theaperture 132 may be configured to permit light traversing the recess 316to pass therethrough. Furthermore, the aperture 132 may cooperate withadditional components of the luminaire 100 to permit the traversal oflight from the recess 316 to the environment.

The aperture 132 may be a void formed by the reflector 130 somewherewithin the periphery of the reflector 130 such that an outer edge of theaperture 132 may define an inner rim of the reflector 130. In thepresent embodiment, the aperture 132 may be formed in a medial region ofthe reflector 130. Furthermore, the aperture 132 may be configured intoany geometric configuration. In the present embodiment, the aperture 132is generally circular. This embodiment is exemplary only, and theaperture 132 may be formed into any other geometric configuration,including, without limitations, ovals, semicircles, triangles, squares,and any other polygon.

Additionally, due to the positioning of the aperture 132 generally atthe center of the reflector 130 and due to the aperture 132 beingconfigured as a circle, the reflector 130 may be described as a frame.This embodiment is exemplary only, and the reflector 130 may be formedinto any other geometric configuration, including, without limitations,ovals, semicircles, triangles, squares, and any other polygon, with theaperture 132 being formed somewhere within the periphery of thegeometric configuration employed. Moreover, the reflector 130 and theaperture 132 may be selectively formed into identical, similar, orentirely different geometric configurations. In forming each of thereflector 130 and the aperture 132, the geometric configuration of alight fixture in which the luminaire 100 may be disposed may beconsidered.

The reflector 130 may be configured to reflect light incident thereupon.More specifically, the interior region of the reflector 130 may beconfigured to reflect a light incident thereupon such that the reflectedlight has an intensity of about 80% to about 99% of the intensity of thelight before being reflected. The reflector 130 may be configured to bereflective by any method known in the art. For example, and withoutlimitation, the reflector 130 may be formed of a material that isinherently reflective of light, and therefore a surface upon whichemitted light may be incident inherently would be reflective. As anotherexample, the reflector 130 may be formed of a material that may bepolished to become reflective. As yet another example, the reflector130, or at least an interior region of the reflector 130, may be formedof a material that is permissive of a material being coated, attached,or otherwise disposed thereupon, the disposed material being reflective.These methods of forming the reflector 130 are exemplary only and do notserve to limit the scope of the invention. All methods known in the artof forming a reflective surface are contemplated and included within thescope of the invention.

Continuing to refer to FIGS. 1B and 2, the interior region of thereflector 130 may include a color conversion layer 272. The colorconversion layer 272 may be configured to receive a source light withina first wavelength range and convert the source light to a convertedlight having a second wavelength range. Additionally, the reflector 130may include two or more color conversion layers 272, wherein each colorconversion layer is positioned upon different sections of the reflector130. Each of the two or more color conversion layers 272 may convertrespective source lights of differing wavelength ranges to respectiveconverted lights of differing wavelength ranges. The reflector 130 mayinclude any number of color conversion layers 272 in any configuration,including overlapping layers. Color conversion layers 272 may be formedof material selected from the group consisting of phosphors, quantumdots, luminescent materials, fluorescent materials, and dyes. Moredetails regarding the enablement and use of a color conversion layer 272may be found in U.S. patent application Ser. No. 13/073,805, entitledMEMS Wavelength Converting Lighting Device and Associated Methods, filedMar. 28, 2011, as well as U.S. patent application Ser. No. 13/234,604,entitled Remote Light Wavelength Conversion Device and AssociatedMethods, filed Sep. 16, 2011, U.S. patent application Ser. No.13/234,371, entitled Color Conversion Occlusion and Associated Methods,filed Sep. 16, 2011, and U.S. patent application Ser. No. 13/357,283,entitled Dual Characteristic Color Conversion Enclosure and AssociatedMethods, the entire contents of each of which are incorporated herein byreference.

The reflector 130, which may be in thermal contact with the light source110 and, where present, the color conversion layer(s) 272, may be formedof a thermally conductive material. Forming the reflector 130 ofthermally conductive material may increase the thermal dissipationcapacity of the luminaire 100 generally. Examples of thermallyconductive materials include metals, metal alloys, ceramics, andthermally conductive polymers. This list is not exhaustive, and allother thermally conductive materials are contemplated and within thescope of the invention.

Referring again to FIGS. 1B and 2, the light guide 140 of the luminaire100 according to an embodiment of the present invention is now discussedin greater detail. The light-emitting elements 216 may be configured toemit light in a direction so as to propagate into the light guide 140.More specifically, the light guide 140 may include one or more lensportions 242 that may be positioned at the circumferential edge of thelight guide 140 into which light reflected by the reflector 130 mayenter the light guide 140. The light guide 140 also may include apropagation region 244 that may retain and spread light within thepropagation region 144 until the light may be emitted substantiallyuniformly from a projection surface 252 of the light guide 140. The oneor more lens portions 242 may be configured to facilitate coupling andredirecting of the light emitted by the LEDs 216 of the light source 110into propagation region 244 of the light guide 140.

For example, and without limitation, the projection surface 252 may bedefined as the lower boundary of the light guide 140. The lens portion242 may redirect reflected light at angles required for the input lightto enter and propagate through the propagation region 244 and,ultimately, to pass through multiple points on the projection surface252 of the light guide 140 at a uniform illuminance. As shown in FIG. 2,the reflector 130 may be configured to cooperate with the light source110 to completely define the region occupied by the light guide 140within the recess 316 of the heat sink 210. More specifically, theaperture 132 in the reflector 130 may be substantially coplanar with theprojection surface 252 of the light guide 140. The aperture 132 may beconfigured so as to cooperate with the projection surface 252 of thelight guide 140 to permit light that traverses the projection surface252 of the light guide 140 to similarly traverse the aperture 132 and topropagate into the environment surrounding the luminaire 100. Exemplarypropagation and projection paths traveled by light emitted from lightsource 110 are shown in FIG. 2 as a series of dashed arrows.

To facilitate emission of the propagation and/or projection of light,the light guide 140 may include a plurality of optical elements 262disposed with the lens portion 242, propagation region 244, and/or theprojection surface 252 of the light guide 140. Optical elements 262 mayoperate to scatter light in more than one direction, and such that thescattered light may be emitted through the projection surface 252 of thelight guide 140. Optical elements 262 may include light-scatteringparticles comprising materials such as, for example and withoutlimitation, glass, ceramic, rubber, silica, inorganic material, andphosphor material. For example, and without limitation, optical elements262 may comprise non-phosphorescent particles that scatter light withoutconverting the wavelength of the input light. Optical elements 262 alsomay comprise non-solid objects embedded in the light guide 140, such as,for example and without limitation, closed liquid-filled and/orgas-filled voids. In some embodiments, optical elements 262 also maycomprise micro-lenses and/or other light shaping structures havingeither diffusing or concentrating properties.

In accordance with various embodiments of the invention, the size, type,and/or density of optical elements 262 may be selected to provideillumination that is substantially uniform in intensity across theprojection surface 252 of the light guide 140. For example, and withoutlimitation, the optical elements 262 may be arranged in the form of aplurality of concentric shapes about the center of the light guide 140.The shapes may be round, ellipsoidal, polygonal, or combinationsthereof, and may present as concentric ridges on one or more exteriorsurfaces of the light guide 140. Also for example, and withoutlimitation, the density of optical elements 262 may increase from theedge of light guide 110 to the center of the light guide 140. Varyingthe density of optical elements 262 in this manner may cause an opticalmean free path within the light guide 140 to decrease as a function ofdistance from the edge of the light guide 140 to the center of the lightguide 140. The diminishing optical mean free path may facilitate anincreasing ratio between the emitted portion and propagated portions ofthe light. The density, size, and/or type of optical elements 262 mayincrease in discrete steps, resulting in concentric areas containingdifferent densities of optical elements 262.

The positioning of the light source 110 and the light-emitting elements216 may take into account the direction that light emitted therefromwill propagate through the light guide 140, as well as any other elementor structure of the luminaire 100 with which light may be incident andmay interact. For example, and without limitation, the light source 110and plurality of light-emitting elements 216 may be positioned to takeinto account the incidence of emitted light upon the reflector 130 andthe reflection of the light therefrom. As described hereinabove, lightreflected from the reflector 130 may propagate through the light guide140 and into the environment surrounding the luminaire 100 through theaperture 132 of the reflector 130 in a predictive direction. Forexample, and without limitation, the light emitted from a light-emittingelement 216 may be reflected by the reflector 130, propagated throughthe light guide 140, and projected through the aperture 132 in adirection that is generally in alignment with the longitudinal axis ofthe luminaire 100.

Light that may escape the light guide 140 and that is incident upon theinterior region of the reflector 130 and/or upon the reflective layer218 may be reflected back into the light guide 140. For example, andwithout limitation, the reflective layer 218 of the light source 110 mayhave reflective properties, such that any reflected light not capturedby the lens portion 142 of light guide 140 may be redirected back intolight guide 140 via reflection from reflective layer 218. Such recycledlight may propagate back through light guide 140 and eventually beredirected to the projection surface 252.

The light guide 140 may be configured so as to permit light thatpropagates through the light guide 140 to combine, forming a combinedlight. The combined light may be a polychromatic light, having multipleconstituent wavelengths of light. In some embodiments, the combinedlight may be a white light. Additional information regarding colorcombination may be found in U.S. patent application Ser. No. 13/107,928,entitled High Efficacy Lighting Signal Converter and Associated Methods,filed May 15, 2011, as well as U.S. Patent Application Ser. No.61/643,308, entitled Tunable Light System and Associated Methods, filedMay 6, 2012, the entire contents of each of which are incorporated byreference herein.

The light guide 140 may be configured into any shape. As depicted inFIG. 1B, the light guide 140 may be configured into a three-dimensionalgeometric shape. In the present embodiment, the light guide 140 may havea thin puck-shaped configuration. Many other shapes of the light guide140 are contemplated and included within the scope of the invention,including, without limitation, spherical, conical, cylindrical,parabolic, pyramidal, and any other geometric configuration that maycollimate, concentrate, refract, reflect, convert, and/or diffuse light.The light guide 140 may comprise any material that may change thedirection of propagation of light, such as, for example and withoutlimitation, polycarbonate, polymethyl methacrylate (PMMA), polyurethane,amorphous nylon, polymethylpentene, polyvinylidene fluoride (PVDF), orother thermoplastic fluorocarbon polymers. Additionally, the light guide140 may be formed either as a separate structure from the reflector 130or as an integral member of the reflector 130.

Referring again to FIGS. 1B and 5, the connector components of theluminaire 100 according to an embodiment of the present invention arenow discussed in greater detail. More specifically, the luminaire maycomprise a mounting ring 150 and a mounting bracket 122.

The mounting ring 150 may be configured to attach, carry, or otherwisebecome engaged with various components of the luminaire 100, includingone or more of the reflector 130, the light guide 140, and the lightsource 110. Such engagement with the mounting ring 150 may fix theposition of a component with respect to the heat sink 120 within theluminaire 100. For example, and without limitation, the heat sink 120may include mounting holes 358 that may align with correspondingthreaded holes 156 in the mounting ring 150 for the purpose of receivingfasteners 158 to secure the mounting ring 150 to the heat sink 120.

Additionally, the mounting ring 150 may be positioned in a relationshipto the aperture 132 of the reflector 130. In the present embodiment, themounting ring 150 may be positioned generally about the aperture 132.More specifically, the mounting ring 150 may be positioned about theperiphery of the aperture 132, generally circumscribing the aperture132. Furthermore, the mounting ring 150 may be positioned so as toresult in desirable emission characteristics of the light guide 140where the light guide 140 may be engaged with the mounting ring 150.Accordingly, the mounting ring 150 may be positioned in relation toemission characteristics of the light source 110 as well as reflectivecharacteristics of the reflector 130 and/or the projectioncharacteristics of the light guide 140.

Additionally, the mounting ring 150 may be formed into a geometricconfiguration. In the present embodiment, the mounting ring 150 may beformed into a generally annular frame configuration. This configurationis exemplary only, and the mounting ring 150 may be formed into anygeometric formation. Moreover, the mounting ring 150 may be formed intoa geometric configuration identical, similar, or different from thegeometric configurations of the aperture 132 and/or the reflector 130.Additionally, the mounting ring 150 may be formed into a geometricconfiguration so as to facilitate engagement with either of the lightsource 110 or the light guide 140, or both.

The mounting ring 150 may be configured to add to the thermaldissipation capacity of the luminaire 100. More specifically, themounting ring 150 may be configured to maximize the conduction of heatfrom any component positioned in thermal communication with the mountingring 150, such as, for example, the light source 110 and/or the heatsink 120. Accordingly, the mounting ring 150 may be configured tomaximize the surface area of the interface between the mounting ring 150and the light source 110, providing that such interfacing does notimpede the propagation of light emitted by the light source 110 and/orprojected by the light guide 140. The mounting ring 150 may be formed ofany thermally conductive material describe hereinabove.

Referring again to FIG. 3B, and continuing to refer to FIGS. 1B and 5,in the present embodiment, the luminaire 100 may include a mountingbracket 122. Securement of the luminaire 100 to a fixture (see, forexample, fixtures 800 and 900 at FIGS. 8 and 9, respectively) or to ajunction box (see, for example, boxes 1000, 1100, and 1200 at FIGS. 10,11, and 12, respectively) may be accomplished by using a mountingbracket 122 and suitable fasteners (not shown) through appropriatelyspaced holes 522 in the mounting bracket 122. Once secured to a hostfixture, the mounting bracket 122 may present an alignment hole with aninternally-threaded bore that may be configured to receive an Edisonconnector portion 340. The Edison connector portion 340 may be formed onthe top surface 320 of the heat sink 120 either as a separate structurefrom the heat sink 120 or as an integral member of the heat sink 120.More specifically, the Edison connector portion 340 of the heat sink 120may be configured to be carried by the mounting bracket 122 so as toremovably attach the heat sink 120 to a junction box and/or to acanister-type fixture by operation of the mounting bracket 122. Thisembodiment is exemplary only and all methods of removable attachment arecontemplated and included within the scope of the invention.

Referring again to FIGS. 1A, 1B, and 2, the outer optic 154 of thepresent embodiment will now be discussed in greater detail. The outeroptic 154 may be configured to be disposed in relation to the lightguide 140 such that light projected from the projection surface 252 ofthe light guide 140 may be incident upon the outer optic 154 andsubsequently may pass through the outer optic 154. For example, andwithout limitation, the outer optic 154 may be carried by one or more ofthe mounting ring 150 and the reflector 130. Also for example, andwithout limitation, the outer optic 154 may be integrally formed withone or more of the mounting ring 150 and the reflector 130.

Additionally, the outer optic 154 may substantially cover and obscurefrom view all of the components of the luminaire 100 that may beconfigured to be carried by the heat sink 120, thereby advantageouslypresenting a low-profile and aesthetically pleasing appearance of theluminaire 100. Referring again to FIG. 1A, the outer optic 154 mayinterface with the interior region of the mounting ring 150 so as toform a seal therebetween, shielding the light guide 140 of the lightsource 110 from the environment surrounding the luminaire 100.

The outer optic 154 may be formed into a geometric configuration thatmay be generally similar to the geometric configuration of the lightguide 140. In the present embodiment, the outer optic 154 may formedinto a circular configuration having a generally flat geometry. Thisconfiguration is exemplary only, and the outer optic 154 may be formedinto any geometric configuration. The outer optic 154 may be made of asuitable material to facilitate shaping of the light emitted by thelight guide 140 to a uniform intensity across the diameter of the outeroptic 154.

For example, the outer optic 154 may be configured to interact withlight projected by the light guide 140 to refract incident light. Theouter optic 154 may be formed in any shape to impart a desiredrefraction. Furthermore, the outer optic 154 may be formed of anymaterial with transparent or translucent properties that comport withthe desired refraction to be performed by the outer optic 154. Moreover,the outer optic 154 may be formed so as to refract light incidentthereupon from the light guide 140 so as to refract the incident lightin a desirous direction. Further, the direction of the refraction mayresult in the propagation of the refracted-reflected light into theenvironment surrounding the luminaire 100 in a desirous direction. Inthe present embodiment, the outer optic 154 may include an outer surfacehaving a plurality of approximately orthogonal sections formed therein.The orthogonal sections may be configured to desirously refract lightincident thereupon. The structure and use of a refracting optic isdescribed in U.S. Patent Application Ser. No. 61/642,205, entitledLuminaire with Prismatic Optic, filed May 3, 2012, which is incorporatedherein by reference.

Additionally, in some embodiments, the outer optic 154 may be configuredto collimate light incident thereupon, such as light projected from thelight guide 140. Additionally, the outer optic 154 may be configured togenerally diffuse, concentrate, and/or reflect light incident thereupon.In some embodiments, the outer optic 154 may include a color conversionlayer. The color conversion layer of the outer optic 154 may beconfigured similarly to the color conversion layer as describedhereinabove for the reflective layer 218.

Referring again to FIGS. 4A, 48, and 5, the electronics housing of theluminaire 100, according to an embodiment of the present invention, isdiscussed in greater detail.

The Edison connector portion 340 of the heat sink 120 may have asubstantially hollow interior configured to receive various componentsand circuitry of the luminaire 100. For example, and without limitation,the Edison connector portion 340 may be configured to contain the powersupply (not shown) and other electronic control devices. Also forexample, and without limitation, the Edison connector portion 340 maypresent a cylinder of sufficient diameter to permit wires to passtherethrough from the light source 110 to the power supply. The Edisonconnector portion 340 also may be configured to connect to aninternally-threaded power supply socket. Those skilled in the art willappreciate that an electrical connector for the light source 110 may beprovided by any type of connector that is suitable for connecting thelight source 110 to a power source. The Edison connector portion 340 ofthe heat sink 120 may, for example, be integrally molded with the heatsink to form a monolithic unit. Alternatively, the Edison connectorportion 340 of the heat sink 120 may be connected to the heat sink byother means such as, for example, an adhesive or welding. Those skilledin the art will appreciate that any connection between the Edisonconnector portion 340 and the heat sink 120 is contemplated by thepresent invention.

Additional details regarding the Edison connector portion 340 andelectronics that may be disposed therein may be found in U.S. patentapplication Ser. No. 13/676,539 titled Low Profile Light Having ConcaveReflector and Associated Methods filed on Nov. 14, 2012, as well as inU.S. patent application Ser. No. 13/476,388 titled Low Profile Light andAccessory Kit For The Same filed on May 21, 2012, in U.S. patentapplication Ser. No. 12/775,310, now U.S. Pat. No. 8,201,968, titled LowProfile Light filed on May 6, 2010, and in U.S. Provisional PatentApplication Ser. No. 61/248,665 filed Oct. 5, 2009, the entire contentsof each of which are incorporated herein by reference.

Referring now to the schematic representation illustrated in FIG. 6, asystem 600 for operating a low profile luminaire 100 according to anembodiment of the present invention will now be described in greaterdetail. The logical components of the luminaire 100 may include acontroller 601 and the light source 110. For example, and withoutlimitation, the light source 110 may comprise a plurality of LEDs 216each arranged to generate a source light. The controller 601 may bedesigned to control the characteristics of the combined light emitted bythe light source 110. The controller 601 may execute control programinstructions using a processor 602 that may accept and executecomputerized instructions, and also a data store 603 which may storedata and instructions used by the processor 602.

The controller 601 may be positioned in electrical communication with apower supply so as to be rendered operational. Additionally, thecontroller 601 may be operably connected to the light source 110 so asto control the operation of the luminaire 100. The controller 601 may beconfigured to operate the light source 110 between operating andnon-operating states, wherein the light source 110 emits light whenoperating, and does not emit light when not operating. Furthermore,where the light source 110 includes a plurality of light-emittingelements 216 (as illustrated in FIG. 4A), the controller 601 may beoperably connected to the plurality of light emitting elements 216.

Yet further, the controller 601 may be operably connected to theplurality of light-emitting elements 216 so as to selectively operateeach light-emitting element of the plurality of light-emitting elements216. Accordingly, the controller 601 may be configured to operate thelight-emitting elements 216 as described hereinabove. Moreover, thecontroller 601 may be configured to operate the light-emitting elements216 so as to control the color, color temperature, brightness, anddistribution of light produced by the luminaire 100 into the environmentsurrounding the luminaire 100 as described hereinabove.

In addition to selective operation of each light-emitting element of theplurality of light-emitting elements 216, the controller 601 may beconfigured to operate each of the plurality of light-emitting elements216 so as to cause each light-emitting element 216 to emit light eitherat a full intensity or a fraction thereof. Many methods of dimming, orreducing the intensity of light emitted by a light-emitting element, areknown in the art. Where the light-emitting elements 216 are LEDs, thecontroller 601 may use any method of dimming known in the art,including, without limitation, pulse-width modulation (PWM) andpulse-duration modulation (PDM). This list is exemplary only and allother methods of dimming a light-emitting element is contemplated andwithin the scope of the invention. Further disclosure regarding PWM maybe found in U.S. Pat. No. 8,384,984 titled MEMS Wavelength ConvertingLighting Device And Associated Methods, filed Mar. 28, 2011, the entirecontents of which are incorporated by reference hereinabove.

Continuing to refer to FIG. 6, the luminaire 100 may comprise a userinterface 604 and/or a sensor 605 configured to program the controller601 to control the emissions characteristics of the light source 110.More specifically, the processor 602 may be configured to receive theinput transmitted from some number of control devices 604, 605 and todirect that input to the data store 603 for storage and subsequentretrieval. For example, and without limitation, the processor 602 may bein data communication with the device 604, 605 through a directconnection and/or through a network connection 606 to a network 607,such as the Internet.

Also for example, and without limitation, the network interface 606 ofthe luminaire 100 may comprise a signal receiver and/or a signaltransmitter. The controller 601 may be programmed to selectively operatethe light source 110 in response to electronic communication receivedfrom an external device 604, 605 through the signal receiver. Thecontroller 601 also may be configured to transmit beam characteristicsto an external device (such as another luminaire 100) through the signaltransmitter to a network 607. More disclosure regarding networkedlighting and attending luminaires may be found in U.S. patentapplication Ser. No. 13/463,020, entitled Wireless Pairing System andAssociated Methods, filed May 3, 2012 and U.S. patent application Ser.No. 13/465,921, entitled Sustainable Outdoor Lighting System andAssociated Methods, filed May 7, 2012, the entire contents of both ofwhich are incorporated herein by reference.

Also for example, and without limitation, the sensor 605 may comprise anoccupancy sensor and/or a timer may be employed for automatic selectionand communication of beam characteristics to the controller 601. Thesensor 605 may transmit a signal to the controller 601 indicating thatthe controller 601 should either operate the light source 110 or ceaseoperation of the light source 110. For example, the sensor 605 may be anoccupancy sensor that detects the presence of a person within a field ofview of the occupancy sensor 605. When a person is detected, theoccupancy sensor 605 may indicate to the controller 601 that the lightsource 110 should be operated so as to provide lighting for the detectedperson. Accordingly, the controller 601 may operate the light source 110so as to provide lighting for the detected person.

Furthermore, the occupancy sensor 605 may either indicate that lightingis no longer required when a person is no longer detected, or either ofthe occupancy sensor 605 or the controller 601 may indicate lighting isno longer required after a period of time transpires during which aperson is not detected by the occupancy sensor 605. Accordingly, ineither situation, the controller 601 may cease operation of the lightsource 110, terminating lighting of the environment surrounding theluminaire 100. The sensor 605 may be any sensor capable of detecting thepresence or non-presence of a person in the environment surrounding theluminaire 100, including, without limitation, infrared sensors, motiondetectors, and any other sensor of similar function known in the art.More disclosure regarding motion-sensing lighting devices and occupancysensors may be found in U.S. patent application Ser. No. 13/403,531,entitled Configurable Environmental Sensing Luminaire, System andAssociated Methods, filed Feb. 23, 2012, and U.S. patent applicationSer. No. 13/464,345, entitled Occupancy Sensor and Associated Methods,filed May 4, 2012, the entire contents of both of which are hereinincorporated by reference.

Referring now to FIG. 7, a method aspect 700 for assembling a lightingdevice adapted to be carried by a lighting fixture will now bediscussed. From the start 705, the assembly method 700 may spawnconcurrent process paths for simultaneously constructing distinctsections of a luminaire 100 according to an embodiment of the presentinvention. One path may include the step of forming the heat sink 120and complementary mounting bracket 122 at Block 710. Forming the heatsink 120 may include fabricating the base 312 to include the mountingholes 358 designed to receive fasteners 158. Forming the heat sink 120may also include forming the Edison connector portion 340 to projectradially outward from the top surface 320 of the base 312, and formingone or more rims 314 to project radially inward from the periphery ofthe base 312. The mounting bracket 122 may be formed to threadablyreceive the exterior of the Edison connector portion 340. At Block 720,electronics components may be fixedly installed into a void defined bythe interior of the Edison connector portion 340 of the heat sink 120.Access to the void may be provided by an opening in the Edison connectorportion 340 that may be coplanar with the base 312. At Block 730 thelight source 110 may be positioned in electrical communication with apower source, and at Block 740 the light source 110 may be positioned inthermal communication with the heat sink 120. The orientation of thelight source 110 may be such that the inner surface 406 of the printedcircuit board 214 that carries one or more LEDs 216 (and, optionally,the reflective layer 218) may be opposite the outer surface 424 of thelight source 110 in thermal communication with the heat sink 120.

From the start 705, a second process path may include the step offorming the mounting ring 150 at Block 715. Forming the mounting ring150 may include fabricating threaded holes 156 that may be designed toreceive fasteners 158, as well as forming the outer optic 154 in ageometric configuration that may interface with the seating structure ofthe mounting ring 150. For example, and without limitation, the outeroptic 154 may be integrally formed with the mounting ring 150. At Block725, the light guide 140 may be installed into the reflector 130 bypositioning the projection surface 252 of the light guide 140 adjacentthe aperture in the reflector 130, and by orienting the edge of thelight guide 140 adjacent the reflective interior portion of thereflector 130. This assembly may then be inserted into the mounting ring150 at Block 735, with the outer portion of the reflector 130interfacing the seating structure of the mounting ring 150.

At Block 750, the separate assemblies created using the two processpaths described above may be oriented for combination into anoperational luminaire 100. This step may include inserting the assembledlight guide 140, reflector 130, and mounting ring 150 into the recess inthe heat sink 120 such that the light guide 140 is positioned adjacentto the light source 110. For example, and without limitation, the lightguide 140 may be positioned to orient one or more specific LEDs 216 tobe in optimal optical communication with one or more ofspecially-designed reflective regions on the reflector 130, withspecially-designed propagation regions of the light guide 140, and withspecially-designed refractive regions of the outer optic 154. After allcomponents are properly oriented as described above, these componentsmay be secured at Block 760 by fasteners 158 applied through themounting holes 358 in the heat sink 120 and into the threaded holes 156of the mounting ring 150. At Block 770, a trim cover 152 may be attachedto the mounting ring 150 in a position that may obscure the reflector130 and/or LEDs 216 of the light source 110 from view from any pointexternal the luminaire 100. For example, the trim cover 152 maycircumferentially snap-fit over the mounting bracket 150 and/or theouter optic 154. The snap-fit arrangement of the trim cover 152 relativeto the outer optic 154 may be such that the trim cover 152 may beremoved in a pop-off manner for maintenance or other purposes.

To provide for a low profile luminaire 100, as illustrated in FIG. 1C,the method 700 may create an assembly of the light source 110, heat sink120, reflector 130, and light guide 140 that may have an overall outsideheight H and an overall outside dimension D such that the ratio of H/Dis equal to or less than 0.25. Dimensions for H and D are contemplatedsuch that the combination of the light source 110, heat sink 120,reflector 130, and light guide 140 may be configured and sized so as to(i) cover an opening defined by an industry standard can-type lightfixture having nominal sizes from three to six inches (see fixture 800at FIG. 8 and fixture 900 at FIG. 9, for example), and (ii) cover anopening defined by an industry standard electrical junction box havingnominal sizes from three to six inches (for example, see boxes 1000,1100, and 1200 at FIGS. 10, 11, and 12, respectively).

Referring now to FIGS. 13, 14, 15, and 16, additional embodiments of thelight guide 140 will now be discussed. As described above, the lightguide 140 may include one or more lens portions 242 that may operate toalter light to project a uniform illuminance into the environmentexterior to the luminaire 100. Alternative to, or in addition to, thelens portions 242, the light guide 140 may be characterized bydeformations in one or more exterior surfaces of the light guide 140that may operate to spread light that is projected into the light guide140 by the LEDs 216 of the light source 110. For example, and withoutlimitation, the deformations may include grooves cut into a surface ofthe light guide 140 opposite the projection surface 252 of the lightguide 140.

As shown in the embodiment depicted in FIG. 13, the grooves may beshaped as concentric circles 1300 of differing radii. Similar to thefunction of the lens portions 242 as described above, the deformations1300 may be configured to facilitate coupling and redirecting of thelight emitted by the LEDs 216 of the light source 110 into thepropagation region 244 of the light guide 140 and, ultimately, emissionof substantially uniform light from the projection surface 252 (seeFIGS. 14, 15, and 16).

For example, and without limitation, the width, depth, and/or radius ofeach of the grooved concentric circles 1300 in the light guide 140 maybe selected to cooperate to redirect reflected light at angles requiredfor the input light to enter and propagate through the propagationregion 244 and, ultimately, to pass through multiple points on theprojection surface 252 of the light guide 140 at a uniform illuminance(see FIG. 16). Each deformation 1300 may operate to scatter light inmore than one direction, and such that the scattered light may beemitted through the projection surface 252 of the light guide 140.

In accordance with various embodiments of the invention, the shape,width, depth, and/or radius of each of the deformations 1300 may beselected to provide illumination that is substantially uniform inintensity across the projection surface 252 of the light guide 140. Thedeformations 1300 may be arranged in the form of a plurality ofconcentric shapes about the center of the light guide 140. For example,and without limitation, the shapes may be round, ellipsoidal, polygonal,or combinations thereof. Also for example, and without limitation, thedensity of deformations 1300 may increase from the edge of light guide110 to the center of the light guide 140. Varying the density ofdeformations 1300 in this manner may cause an optical mean free pathwithin the light guide 140 to decrease as a function of distance fromthe edge of the light guide 140 to the center of the light guide 140.The diminishing optical mean free path may facilitate an increasingratio between the emitted portion and propagated portions of the light.The density, width, and/or depth of the deformations 1300 may increasein discrete steps, resulting in concentric areas containing differentdensities of deformations 1300.

A skilled artisan will note that one or more of the aspects of thepresent invention may be performed on a computing device. The skilledartisan will also note that a computing device may be understood to beany device having a processor, memory unit, input, and output. This mayinclude, but is not intended to be limited to, cellular phones, smartphones, tablet computers, laptop computers, desktop computers, personaldigital assistants, etc. FIG. 17 illustrates a model computing device inthe form of a computer 610, which is capable of performing one or morecomputer-implemented steps in practicing the method aspects of thepresent invention. Components of the computer 610 may include, but arenot limited to, a processing unit 620, a system memory 630, and a systembus 621 that couples various system components including the systemmemory to the processing unit 620. The system bus 621 may be any ofseveral types of bus structures including a memory bus or memorycontroller, a peripheral bus, and a local bus using any of a variety ofbus architectures. By way of example, and not limitation, sucharchitectures include Industry Standard Architecture (ISA) bus, MicroChannel Architecture (MCA) bus, Enhanced ISA (EISA) bus, VideoElectronics Standards Association (VESA) local bus, and PeripheralComponent Interconnect (PCI).

The computer 610 may also include a cryptographic unit 625. Briefly, thecryptographic unit 625 has a calculation function that may be used toverify digital signatures, calculate hashes, digitally sign hash values,and encrypt or decrypt data. The cryptographic unit 625 may also have aprotected memory for storing keys and other secret data. In otherembodiments, the functions of the cryptographic unit may be instantiatedin software and run via the operating system.

A computer 610 typically includes a variety of computer readable media.Computer readable media can be any available media that can be accessedby a computer 610 and includes both volatile and nonvolatile media,removable and non-removable media. By way of example, and notlimitation, computer readable media may include computer storage mediaand communication media. Computer storage media includes volatile andnonvolatile, removable and non-removable media implemented in any methodor technology for storage of information such as computer readableinstructions, data structures, program modules or other data. Computerstorage media includes, but is not limited to, RAM, ROM, EEPROM, FLASHmemory or other memory technology, CD-ROM, digital versatile disks (DVD)or other optical disk storage, magnetic cassettes, magnetic tape,magnetic disk storage or other magnetic storage devices, or any othermedium which can be used to store the desired information and which canbe accessed by a computer 610. Communication media typically embodiescomputer readable instructions, data structures, program modules orother data in a modulated data signal such as a carrier wave or othertransport mechanism and includes any information delivery media. Theterm “modulated data signal” means a signal that has one or more of itscharacteristics set or changed in such a manner as to encode informationin the signal. By way of example, and not limitation, communicationmedia includes wired media such as a wired network or direct-wiredconnection, and wireless media such as acoustic, radio frequency,infrared and other wireless media. Combinations of any of the aboveshould also be included within the scope of computer readable media.

The system memory 630 includes computer storage media in the form ofvolatile and/or nonvolatile memory such as read only memory (ROM) 631and random access memory (RAM) 632. A basic input/output system 633(BIOS), containing the basic routines that help to transfer informationbetween elements within computer 610, such as during start-up, istypically stored in ROM 631. RAM 632 typically contains data and/orprogram modules that are immediately accessible to and/or presentlybeing operated on by processing unit 620. By way of example, and notlimitation, FIG. 17 illustrates an operating system (OS) 634,application programs 635, other program modules 636, and program data637.

The computer 610 may also include other removable/non-removable,volatile/nonvolatile computer storage media. By way of example only,FIG. 17 illustrates a hard disk drive 641 that reads from or writes tonon-removable, nonvolatile magnetic media, a magnetic disk drive 651that reads from or writes to a removable, nonvolatile magnetic disk 652,and an optical disk drive 655 that reads from or writes to a removable,nonvolatile optical disk 656 such as a CD ROM or other optical media.Other removable/non-removable, volatile/nonvolatile computer storagemedia that can be used in the exemplary operating environment include,but are not limited to, magnetic tape cassettes, flash memory cards,digital versatile disks, digital video tape, solid state RAM, solidstate ROM, and the like. The hard disk drive 641 is typically connectedto the system bus 621 through a non-removable memory interface such asinterface 640, and magnetic disk drive 651 and optical disk drive 655are typically connected to the system bus 621 by a removable memoryinterface, such as interface 650.

The drives, and their associated computer storage media discussed aboveand illustrated in FIG. 17, provide storage of computer readableinstructions, data structures, program modules and other data for thecomputer 610. In FIG. 17, for example, hard disk drive 641 isillustrated as storing an OS 644, application programs 645, otherprogram modules 646, and program data 647. Note that these componentscan either be the same as or different from OS 633, application programs633, other program modules 636, and program data 637. The OS 644,application programs 645, other program modules 646, and program data647 are given different numbers here to illustrate that, at a minimum,they may be different copies. A user may enter commands and informationinto the computer 610 through input devices such as a keyboard 662 andcursor control device 661, commonly referred to as a mouse, trackball ortouch pad. Other input devices (not shown) may include a microphone,joystick, game pad, satellite dish, scanner, or the like. These andother input devices are often connected to the processing unit 620through a user input interface 680 that is coupled to the system bus,but may be connected by other interface and bus structures, such as aparallel port, game port or a universal serial bus (USB). A monitor 691or other type of display device is also connected to the system bus 621via an interface, such as a graphics controller 690. In addition to themonitor, computers may also include other peripheral output devices suchas speakers 697 and printer 696, which may be connected through anoutput peripheral interface 695.

The computer 610 may operate in a networked environment using logicalconnections to one or more remote computers, such as a remote computer680. The remote computer 680 may be a personal computer, a server, arouter, a network PC, a peer device or other common network node, andtypically includes many or all of the elements described above relativeto the computer 610, although only a memory storage device 681 has beenillustrated in FIG. 17. The logical connections depicted in FIG. 17include a local area network (LAN) 671 and a wide area network (WAN)673, but may also include other networks 140. Such networkingenvironments are commonplace in offices, enterprise-wide computernetworks, intranets and the Internet.

When used in a LAN networking environment, the computer 610 is connectedto the LAN 671 through a network interface or adapter 670. When used ina WAN networking environment, the computer 610 typically includes amodem 672 or other means for establishing communications over the WAN673, such as the Internet. The modem 672, which may be internal orexternal, may be connected to the system bus 621 via the user inputinterface 660, or other appropriate mechanism. In a networkedenvironment, program modules depicted relative to the computer 610, orportions thereof, may be stored in the remote memory storage device. Byway of example, and not limitation, FIG. 17 illustrates remoteapplication programs 685 as residing on memory device 681.

The communications connections 670 and 672 allow the device tocommunicate with other devices. The communications connections 670 and672 are an example of communication media. The communication mediatypically embodies computer readable instructions, data structures,program modules or other data in a modulated data signal such as acarrier wave or other transport mechanism and includes any informationdelivery media. A “modulated data signal” may be a signal that has oneor more of its characteristics set or changed in such a manner as toencode information in the signal. By way of example, and not limitation,communication media includes wired media such as a wired network ordirect-wired connection, and wireless media such as acoustic, RF,infrared and other wireless media. Computer readable media may includeboth storage media and communication media.

Some of the illustrative aspects of the present invention may beadvantageous in solving the problems herein described and other problemsnot discussed which are discoverable by a skilled artisan. While theabove description contains much specificity, these should not beconstrued as limitations on the scope of any embodiment, but asexemplifications of the presented embodiments thereof. Many otherramifications and variations are possible within the teachings of thevarious embodiments. While the invention has been described withreference to exemplary embodiments, it will be understood by thoseskilled in the art that various changes may be made and equivalents maybe substituted for elements thereof without departing from the scope ofthe invention. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the inventionwithout departing from the essential scope thereof. Therefore, it isintended that the invention not be limited to the particular embodimentdisclosed as the best or only mode contemplated for carrying out thisinvention, but that the invention will include all embodiments fallingwithin the scope of the appended claims. Also, in the drawings and thedescription, there have been disclosed exemplary embodiments of theinvention and, although specific terms may have been employed, they areunless otherwise stated used in a generic and descriptive sense only andnot for purposes of limitation, the scope of the invention therefore notbeing so limited. Moreover, the use of the terms first, second, etc. donot denote any order or importance, but rather the terms first, second,etc. are used to distinguish one element from another. Furthermore, theuse of the terms a, an, etc. do not denote a limitation of quantity, butrather denote the presence of at least one of the referenced item.

Thus, the scope of the invention should be determined by the appendedclaims and their legal equivalents, and not by the examples given.

That which is claimed is:
 1. A luminaire comprising: a heat sink; alight source carried by the heat sink and configured to emit a sourcelight, the light source comprising a heat spreader having an innersurface and an outer surface, and a plurality of light-emitting diodes(LEDs) carried by a circuit board and disposed generally along an outerperipheral perimeter portion of the inner surface of the heat spreader,and positioned in thermal communication with the heat spreader; a lightguide comprising: a propagation region comprising a lens including solidoptical elements comprising light scattering particles made from atleast one of glass, ceramic, rubber, silica, inorganic material, andphosphor material, and non-solid optical elements comprising liquid andgas, and wherein the lens comprises a plurality of micro-lenses; andwherein the light guide is configured to scatter and concentrate lightin multiple directions.
 2. The luminaire according to claim 1 whereinthe micro-lenses are one of circular, oval, rectangular, square, andpolygonal in shape.
 3. The luminaire according to claim 1 wherein acombination of the light source and the heat sink is so dimensioned asto cover an opening defined by a nominally sized four-inch can lightfixture, and to cover an opening defined by a nominally sized four-inchelectrical junction box.
 4. The luminaire according to claim 1 wherein acombination of the light source and the heat sink is so dimensioned asto cover an opening defined by a nominally sized four-inch can lightfixture, and to cover an opening defined by a nominally sized four-inchelectrical junction box.